title: A clinical prediction rule for the diagnosis of coronary artery disease: validation, updating, and extension.
abstract: OBJECTIVE
  The aim was to validate, update, and extend the Diamond-Forrester model for estimating the probability of obstructive coronary artery disease (CAD) in a contemporary cohort.
  
  
  RESULTS
  Prospectively collected data from 14 hospitals on patients with chest pain without a history of CAD and referred for conventional coronary angiography (CCA) were used. Primary outcome was obstructive CAD, defined as ≥ 50% stenosis in one or more vessels on CCA. The validity of the Diamond-Forrester model was assessed using calibration plots, calibration-in-the-large, and recalibration in logistic regression. The model was subsequently updated and extended by revising the predictive value of age, sex, and type of chest pain. Diagnostic performance was assessed by calculating the area under the receiver operating characteristic curve (c-statistic) and reclassification was determined. We included 2260 patients, of whom 1319 had obstructive CAD on CCA. Validation demonstrated an overestimation of the CAD probability, especially in women. The updated and extended models demonstrated a c-statistic of 0.79 (95% CI 0.77-0.81) and 0.82 (95% CI 0.80-0.84), respectively. Sixteen per cent of men and 64% of women were correctly reclassified. The predicted probability of obstructive CAD ranged from 10% for 50-year-old females with non-specific chest pain to 91% for 80-year-old males with typical chest pain. Predictions varied across hospitals due to differences in disease prevalence.
  
  
  CONCLUSIONS
  Our results suggest that the Diamond-Forrester model overestimates the probability of CAD especially in women. We updated the predictive effects of age, sex, type of chest pain, and hospital setting which improved model performance and we extended it to include patients of 70 years and older.
authors.affiliation: Department of Epidemiology, Erasmus University Medical Center, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
authors.forename: Tessa S S
authors.initials: TS
authors.lastname: Genders
authors.forename: Ewout W
authors.initials: EW
authors.lastname: Steyerberg
authors.forename: Hatem
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authors.lastname: Alkadhi
authors.forename: Sebastian
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authors.lastname: Leschka
authors.forename: Lotus
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authors.lastname: Desbiolles
authors.forename: Koen
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authors.lastname: Nieman
authors.forename: Tjebbe W
authors.initials: TW
authors.lastname: Galema
authors.forename: W Bob
authors.initials: WB
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authors.forename: Nico R
authors.initials: NR
authors.lastname: Mollet
authors.forename: Pim J
authors.initials: PJ
authors.lastname: de Feyter
authors.forename: Filippo
authors.initials: F
authors.lastname: Cademartiri
authors.forename: Erica
authors.initials: E
authors.lastname: Maffei
authors.forename: Marc
authors.initials: M
authors.lastname: Dewey
authors.forename: Elke
authors.initials: E
authors.lastname: Zimmermann
authors.forename: Michael
authors.initials: M
authors.lastname: Laule
authors.forename: Francesca
authors.initials: F
authors.lastname: Pugliese
authors.forename: Rossella
authors.initials: R
authors.lastname: Barbagallo
authors.forename: Valentin
authors.initials: V
authors.lastname: Sinitsyn
authors.forename: Jan
authors.initials: J
authors.lastname: Bogaert
authors.forename: Kaatje
authors.initials: K
authors.lastname: Goetschalckx
authors.forename: U Joseph
authors.initials: UJ
authors.lastname: Schoepf
authors.forename: Garrett W
authors.initials: GW
authors.lastname: Rowe
authors.forename: Joanne D
authors.initials: JD
authors.lastname: Schuijf
authors.forename: Jeroen J
authors.initials: JJ
authors.lastname: Bax
authors.forename: Fleur R
authors.initials: FR
authors.lastname: de Graaf
authors.forename: Juhani
authors.initials: J
authors.lastname: Knuuti
authors.forename: Sami
authors.initials: S
authors.lastname: Kajander
authors.forename: Carlos A G
authors.initials: CA
authors.lastname: van Mieghem
authors.forename: Matthijs F L
authors.initials: MF
authors.lastname: Meijs
authors.forename: Maarten J
authors.initials: MJ
authors.lastname: Cramer
authors.forename: Deepa
authors.initials: D
authors.lastname: Gopalan
authors.forename: Gudrun
authors.initials: G
authors.lastname: Feuchtner
authors.forename: Guy
authors.initials: G
authors.lastname: Friedrich
authors.forename: Gabriel P
authors.initials: GP
authors.lastname: Krestin
authors.forename: M G Myriam
authors.initials: MG
authors.lastname: Hunink
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D060050:Angina, Stable / Q000209:etiology; D002138:Calibration; D023921:Coronary Stenosis / Q000175:diagnosis*; D003661:Decision Support Techniques; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011336:Probability; D011446:Prospective Studies; D012372:ROC Curve; D018570:Risk Assessment